MASK AND MANUFACTURING METHOD OF MASK
A mask includes a plurality of line patterns provided on a substrate, the plurality of line patterns each including a line comprising a plurality of first layers and a plurality of second layers alternately stacked on the substrate. The lines of the plurality of line patterns extend in a first direction and the lines of the plurality of line patterns are spaced in a second direction crossing the first direction. A line of one of the plurality of line patterns has a first portion and a second portion on a side of the first portion in the first direction, the first portion wider than the second portion in the second direction.
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2016-051687, filed on Mar. 15, 2016, the entire contents of which are incorporated herein by reference.
FIELDEmbodiments described herein relate generally to a mask and a method of manufacturing a mask.
BACKGROUNDDefects may be formed on the mask used in a lithography process. In this case, defects on the device, which is manufactured using the mask, are formed as a result of the defects on the mask.
Embodiments will now be described with reference to the drawings. The drawings are schematic or conceptual; and the relationships between the thicknesses and widths of portions shown in the drawings, the proportions of sizes between portions, etc., are not necessarily the same as the values thereof in an actual mask. The dimensions and/or the proportions may be illustrated differently between the drawings, even in the case where the same portion is illustrated. The same portions within the various drawings are marked with the same numerals and letters, and a repeated detailed description is omitted as appropriate, and primarily the different portions are described.
A mask according to an embodiment includes a plurality of line patterns provided on a substrate, the plurality of line patterns each including a line comprising a plurality of first layers and a plurality of second layers alternately stacked on the substrate. The lines of the plurality of line patterns extend in a first direction and the lines of the plurality of line patterns are spaced in a second direction crossing the first direction. A line of one of the plurality of line patterns has a first portion, and a second portion located on a side of the first portion in the second direction, the first portion wider than the second portion in the second direction.
As shown in
For example, the individual lines 20 of the plurality of line patterns 20 extend in a first direction. The plurality of lines of the line patterns 20 are spaced apart in a second direction intersecting the first direction.
The first direction is taken as an X-direction. One direction perpendicular to the X-direction is taken as a Y-direction. The second direction is corresponding to the Y-direction in a sample of the
Individual lines among the plurality of line patterns 20 are spaced from one another at a pitch (first pitch PT1). The plurality of line patterns 20 are line and space patterns. The plurality of line patterns 20 have line portions which have one reflectivity with respect to an EUV (Extreme Ultraviolet) illumination and space portions therebetween which have a different reflectivity than the line portions. The first pitch PT1 is defined, for example, as the distance between the center of one line of plurality of line patterns 20 and the center of an adjacent line of the plurality of line patterns 20 in the second direction (Y-direction).
As shown the
Mask 110 is, for example, an EUV mask. An EUV mask is used for EUV lithography (Extreme Ultraviolet Lithography: EUVL). EUV is used as the exposure light (energy) in EUV lithography. A wave length of the exposure light is, for example, about 13.5 nm. The mask 110 is, for example, a reflective EUV mask. The plurality of the first layers 21 and the plurality of the second layers 22 reflect the EUV energy received thereat.
In one embodiment, the widest width, in the Y direction, of a line in a portion of the plurality of line patterns 20 (first portion 20a) in the Y direction is larger than the width in the Y direction of another portion of the same line among the plurality of the line patterns 20 (first portion 20b). Thereby, generation of a defect in workpiece formed using the mask can be decreased (controlled).
That is, the plurality of line patterns 20 are originally formed with substantially the same line width. However, in the process of the manufacturing the mask 110, a foreign material (particle 40 shown in the
In the embodiment, the width of a portion of a line (first portion 20a) in the plurality of the line patterns 20 is larger than the width of another portion (second portion 20b) of the same line in the plurality of the line patterns 20. As shown in the
The second portion 20b is, for example, a fine portion (a normal portion). The first portion 20a is a portion which is locally enlarged. The locally enlarged portion corresponds to a modified (corrected) portion. By enlarging the portion, an effect of the foreign material is controlled and generation of a defect in the workpiece made using the mask is controlled.
In the embodiment, a case which the foreign material is present and a case which the foreign material is not present may exist. For example, in a case where the foreign material is small, or in a case where a property of the foreign material is similar to a property of a region around the foreign material, it may be difficult to observe the foreign material.
Below is a description of examples of the foreign material and the defect attributed in the foreign material.
For example, as shown in the
As shown in the
For example, a defect (phase defect portion) 26 is generated due to the presence of the particle 40. For example, the first portion 20a has a defective portion (phase defect portion) 26. The first portion 20a overlies the particle 40 in Z-direction. On the other hand, the second portion 20b does not overlie the particle 40 in Z-direction. In this sample, a height of an upper surface of the stack of first and second layers 21, 22 on the defective portion 26 is different from a height of an upper surface of the stack of first and second layers 21, 22 on the second portion 20b. For example, the upper surface on the defective portion 26 is a convex surface. For example, a surface roughness of the upper surface on the first portion 20a is rougher than a surface roughness of the upper surface on the second portion 20b.
For example, a reflectivity of the first portion 20a including the defect potion 26 is lower than a reflectivity of the second portion 20b. The reflectivity of the first portion 20a and the reflectivity of the second portion 20b are the reflectivity of the portions with respect to EUV energy or light.
As described above, in the case where the phase defect is generated in an EUV mask, the intensity of EUV reflection (reflected light) reaching an intended location on the workpiece being processed with the mask from the defective portion 26 is lower than an intensity of EUV reflection (reflected light) from a portion of the mask in which the phase defect does not exist. Therefore, a defect (device defect) may be generated in the workpiece processed by the mask 110 in the EUV lithography.
In the mask 110 which relates to the embodiment, the width of the first portion 20a which includes the defective portion 26 is made larger than the width of the second portion 20b. A reflecting area of the first portion 20a, which includes the defective portion 26, is locally larger than a reflecting area of the line adjacent to the first portion 20b. In the embodiment, a localized reduction of the intensity in EUV reflectivity as a result of the defective portion 26 can thus be offset. The depression of the intensity in EUV reflectivity is due to the phase defect. Therefore, the defect occurring on the workpiece processed with the mask can be controlled during the EUV lithography.
In the embodiment, the distance between the side of the first portion 20a of a line and a non-defective portion of an adjacent line 20 is 0.1 to 0.8 times the distance between the second portion 20b of the same line and the same adjacent line 20. In case the distance is smaller, the negative impact on the mask due to the presence of the foreign material cannot be offset. In the case the distance is too large, the negative impact due to the first portion 20a can still be great.
On the other hand, the length of the first portion 20a in the X-direction is shorter than the length of the second portion 20b in the X-direction. That is, the portion which is modified (corrected) is a local, small portion of the line 20. The first portion 20a is adjacent to, and overlies, the particle 40.
In the embodiment, the first layer 21 includes molybdenum (Mo), for example. Furthermore, in this example, a third layer 27 is supplied on a stacked body ML. The third layer 27 is, for example, a capping layer. The third layer 27 includes, for example, ruthenium (Ru). In the mask 110, the third layer 27 may not be supplied.
[Manufacturing Method According to First Embodiment]
A mask production method according to the first embodiment is described herein. For example, the mask of
As shown in
As shown in
As shown
One of the lines in the plurality of mask line patterns 30 includes a first mask portion 30a and a second mask portion 30b as shown in
After patterning of the mask film is performed (step S13 in
As shown in
As shown in
As shown in
In the stacked body, the portion of the stacked body and the third film 27f masked by the first mask portion 30a and the correction (modifying) pattern 35 becomes a first portion 20a. A portion of the stacked body and the third film 27f masked by the second mask portion 30b becomes a second portion 20b. Thereby, a mask 110 is formed.
As a reference, to solve the problem due to the mask stacked body defect, there is another EUV mask manufacturing method. The other EUV mask manufacturing method includes, for example, removing a portion of the stacked body and forming a new portion of the stacked body at the location corresponding to the portion including the foreign material, and thereby modifying the EUV mask. However it is difficult to conduct the other EUV mask manufacturing method because a quite high precision technique is required.
In the embodiment, for example, the correction (modifying) pattern 35 is formed after patterning the mask film 30f (ex. hard mask) on the stacked film MLf. Forming the correction (modifying) pattern 35 is conducted before patterning the stacked film 35MLf. By using the correction (modifying) pattern 35 in addition to the mask film 30f as the portion of the hard mask surrounding the defect portion 36, the first portion 20a including the defect 26 is formed. The width of the first portion 20a is wider than the width of the second portion 20b in the line pitch direction. In the embodiment, the size of the line pattern 20 including the defective portion 26 is resultantly modified. As described above, it is easy to manufacture the EUV mask including a process to modify the defective portion 26. By using the mask 110, generating a defect in a device made using the mask may be reduced or eliminated.
The correction (modifying) pattern is formed in regions between the plurality of line patterns in the embodiment. For example, the plurality of the mask line patterns 30 include a first line 31, a second line 32 and a third line 33 shown in the views of
Below is a description of an example of a process of step S14 to step S17 in
In step S14 shown in
In step S15 shown in
[Manufacturing Method According to Second Embodiment]
Below is a description of a mask manufacturing method according to a second embodiment.
At first, in the second embodiment, processes shown in
Next, a correction (modifying) pattern 35 is formed to cover a portion of a line 30b above the defective portion 26 in the mask line pattern 30. The correction (modifying) pattern 35 is also formed in a portion of the region between the line 30b and the lines 30b of the mask line patterns 30 which are next to the one mask line pattern 30 on either side thereof. As shown in
In the embodiment, the correction (modifying) pattern 35 is also formed above the defective portion 26. Therefore, it is easier to form the correction (modifying) patterns 35 than selectively forming the correction (modifying) patterns 35 on both sides of the first mask portion 30a.
[Manufacturing Method According to Third Embodiment]
The third embodiment is related to a mask manufacturing method. In the manufacturing method according to the third embodiment, drawing data is modified based on the defect. That is, a drawing pattern is modified. For example, the mask described in the first embodiment is obtained by this manufacturing method.
As discussed in
The stacked film MLf and the mask film 30f is checked (step S22). In this process, a position of the defect (phase defect) and a size of the defect are estimated.
An effect on the image transferring in the lithography process is then estimated (step S23). The effect on the image transferring is due to the defect which is detected. For example, data which is obtained as a result of the checking and the drawing data are compared. And the effect on image transferring in the lithography process is estimated. The effect is due to the defect. And data of a defective portion 26 is extracted. The effect on image transferring during the lithography is, for example, decreasing an intensity of reflection (reflected light). The effect on image transferring is due to the defective potion 26.
Drawing data for writing the image pattern on the resist pattern on the mask film 30f is modified based on data related to the defect which is detected in the checking process (step S24). The drawing pattern is modified based on the defect (defect portion). For example, the feature size of the modified pattern is changed in the drawing pattern which is set in advance. Thereby, drawing data (drawing pattern data) in which the modified pattern is provided is obtained.
Furthermore, a pattern is drawn on the resist over the mask film 30f based on the modified drawing data (step S25). The mask line pattern 30 is formed on the mask film 30f. In the mask line pattern 30, a width of a portion which overlies the defect (defective portion 26) is larger than a width of a portion which does not overlie the defect (defective portion 26). For example, during drawing of the drawing pattern, a modified drawing pattern is drawn on the resist overlying the mask film after the position adjustment using the alignment mark as a reference position for locating the location of the defect. A mask line pattern 30 is formed from the mask film 30f based on this drawing. Therefore, the mask film 30f becomes the mask line pattern 30.
The state as described above is shown in
As shown in
A fine-tune pattern may be conducted by a defect modifying (correction) device after the step S25. A defect modifying (correction) apparatus has, for example, a focused ion beam apparatus or an electron beam apparatus to locally modify the mask film 30.
Furthermore, the stacked film MLf is etched using the mask pattern as a mask as shown in
In this sample, a drawing pattern which includes the modified (correction) pattern is drawn in the resist layer overlying the mask film 30f. Therefore, the impact of the defect can be controlled without forming the modifying (correction) pattern in another process.
In the extreme ultraviolet lithography (EUVL) process to manufacture a semiconductor device, for example, an EUV mask which has a multilayer film (layers reflective of EUV light) and a patterned shielding mask is used. The multilayer film on which molybdenum (Mo) thin films and silicon (Si) thin films are stacked is formed on the mask substrate. The patterned shielding mask includes, for example, tantalum. In an EUVL process, by using this EUV mask, transferring to the wafer may not be obtained with predetermined accuracy due to generating a shadow in the patterning direction. When oblique-incidence is conducted, the shadow may be generated because an absorbing body is so thick (shadowing effect). There is an EUV mask which is an attenuated multilayer type EUV mask to obtain a lower (less) shadowing effect. However, it is more difficult to modify a defect when using the attenuated multilayer type EUV mask than when using the pattern absorbing body type EUV mask because it is necessary to process the multilayer film directly during manufacturing the attenuated multilayer type EUV mask. In particular, it is difficult to process the multilayer film with high accuracy while maintaining the desired EUV reflection properties. A way to modify (correct) the defect by correcting the absorbing body is a common way. However, it is impossible to apply this way to modify the defect by correcting the absorbing body to the attenuated multilayer type EUV.
In the embodiment, for example, one of a plurality of line patterns 20 has a first portion which is wider than the other portion (second portion 20b).
As described above in each embodiment, a foreign material (particle 40) is shown as a sample of a defect which causes the phase defect. However, the phase defect may be caused by a convex portion on the substrate or a depression (concave) portion on the substrate. Below is a description of examples of the phase defect.
As shown in
As shown in
While certain embodiments have been described, these embodiments have been presented by way of example only, and are intended to limit the scope of the invention. Indeed, the novel devices and methods described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modification as would fall within the scope and spirit of the inventions.
Claims
1. A mask comprising:
- a plurality of line patterns provided on a substrate, the plurality of line patterns each including a line comprising a plurality of first layers and a plurality of second layers alternately stacked on the substrate, wherein
- the lines of the plurality of line patterns extend in a first direction and the lines of the plurality of line patterns are spaced in a second direction crossing the first direction; and
- a line of one of the plurality of line patterns has a first portion and a second portion on a side of the first portion in the first direction, the first portion wider than the second portion in the second direction.
2. The mask according to claim 1, wherein a first height of a first surface above the substrate in the first portion is different from a second height of a second surface above the substrate in the second portion.
3. The mask according to claim 2, wherein the first height is higher than the second height.
4. The mask according to claim 1, wherein a part of the first portion has a different height above the substrate than another part of the first portion.
5. The mask according to claim 1, wherein a distance between the first portion of the line and an adjacent line is 0.1 times to 0.8 times the distance between the second portion of the line and the adjacent line.
6. The mask according to claim 1, wherein the first layers include molybdenum and the second layers include silicon.
7. The mask according to claim 1, wherein the first portion includes a particle located between:
- one of the first and second layers and the substrate, or
- one of the first layers and one of the second layers.
8. The mask according to claim 1, wherein the first portion includes a particle on the substrate.
9. The mask according to claim 1, wherein each line of the plurality of line patterns further comprise a third layer; and the first and second layers are provided between the third layer and the substrate.
10. The mask according to claim 9, wherein the third layer includes ruthenium.
11. A mask manufacturing method comprising:
- forming a plurality of lines in a pattern on a stacked film, the stacked film including a plurality of first layers and a plurality of second layers arranged alternately;
- checking at least one of the plurality of lines, or the stacked film before forming the plurality of lines thereon;
- forming a correction pattern around a portion of at least one of the plurality of lines which corresponds to a defective region, the defective region being detected during the checking; and
- processing the stacked film by using the plurality of lines and the correction pattern as a mask.
12. The method according to claim 11, wherein the plurality of lines include a first line, a second line and a third line,
- the first line is formed between the second line and the third line,
- the first line includes the defective region which overlies a defect in the stacking direction of the plurality of first layers and the plurality of second layers, and
- wherein the correction pattern is connected to the defective region of the first line in a location between the defective region and the second line, and between the defective region and the third line.
13. The method according to claim 12, wherein the correction pattern is also formed above the portion of the first line having the defective region.
14. The method according to claim 13, wherein the lines includes tantalum.
15. The method according to claim 13, wherein the correction pattern includes at least one of tantalum and silicon oxide.
16. A mask manufacturing method comprising:
- forming a mask film on a stacked film, the stacked film including a plurality of first layers and a plurality of second layers alternately arranged in a stack;
- checking the mask film and the stacked film;
- modifying drawing data based on data related to a defect detected during the checking;
- forming a mask line pattern with the mask film using the modified drawing data, the mask line pattern having a portion overlying the defect and a portion not overlying the defect, the portion overlying the defect being wider than the portion not overlying the defect; and
- processing the stacked film using the mask line pattern as a mask.
17. The method according to claim 16, wherein the mask film includes tantalum.
18. The method according to claim 16, wherein the first films include tantalum, and the second films include silicon.
19. The method according to claim 16, wherein:
- the mask line pattern includes a first line, a second line and a third line, each of the first, second and third lines extending in a first direction and spaced from one another in a second direction, the second line located between the first and second lines;
- the second line includes a defect therein in a first portion thereof, and does not include a defect in a second portion thereof; and
- the distance between the first portion of the second line and the first line is 0.1 to 0.8 times the distance between the second portion of the second line and the first line.
20. The method according to claim 19, wherein the defect is one of a recess or a convex portion of the surface of the stacked film.
Type: Application
Filed: Mar 3, 2017
Publication Date: Sep 21, 2017
Patent Grant number: 10274821
Inventors: Keiko MORISHITA (Yokohama Kanagawa), Shingo KANAMITSU (Kawasaki Kanagawa)
Application Number: 15/449,853